Denmark has been given as an example of where it was seen as one of the first steps in easing the lockdown
https://edition.cnn.com/2020/04/17/europe/denmark-coronavirus-first-school-intl/index.html
Schools have remained open in UK. Some have small numbers; some with lots of children with special needs or children of key workers have greater numbers.
The proposal is for small classes of maybe 15 (seems too high to me but it depends on room size and number of TAs), but as it's only year/1 and Year 6 they should be able to spread them more thinly between teachers and rooms.
I'd feel nervous about going back.
I can see why primary teachers would be happy to continue getting full pay for maybe one day a week on a rota rather than returning on a maybe 4-5 day a week basis